The present invention relates to the cutting of windows and designs in so-called artist's mats or mat board, and more specifically to an apparatus and method for cutting such apertures in configurations heretofore achievable only by custom hand-cutting by an experienced artisan, but with much greater accuracy and in volumes greatly exceeding those achievable by hand-cutting.
The framing of photographs, prints and other substantially, two-dimensional works, such as certificates, diplomas, etc., is normally effected by using a mat with a window cut therein laid over the work to enhance and focus the viewer's attention on the work. The stock from which the mat is formed is usually paper in the form of cardboard, in some instances having a surface finish of a different color than the interior of the board, chosen to complement the work, the frame for the work, the color scheme of a room in which the work is to be displayed, or it may be ivory, white or other neutral shades. The texture of the board can be rough or smooth, imprinted or embossed with a secondary color, design or pattern, or covered with a fabric or other material.
While it is possible, and in most cases easier, to cut a window in mat board using a straight cut, that is to say a cut perpendicular to the plane of the mat, esthetics and purchaser preference dictate that the window be cut on a bevel, or oblique angle to the plane of the board. Commonly used bevel angles are 30.degree., 45.degree. and 60.degree. to the plane of the mat, the increasing angle giving less exposure of the interior color of the mat to the viewer as the window border provided by the cut becomes narrower. It is also known to laminate two different colors of mat board, with aligned but differently sized windows to provide a contrasting border around the work to be framed.
Throughout the years, in fact for the past century, many attempts have been made to expedite the making of bevel cuts, and to increase both accuracy of such cuts beyond that achievable by manual cutting. U.S. Pat. Nos. 3,967,519, 3,996,827, 4,158,977, 4,413,542, 4,440,055, 4,590,834, 4,747,330 and 4,798,112 each disclose certain improvements and enhancements for manual mat cutting with blades mounted for bevel cuts on rails, trolleys or other supports to permit the making of linear bevel cuts. Others working in the art have attempted to automate the cutting process to some extent, generally by mounting cutting blades on pneumatic cylinders for advancement into and retraction from the mat board, and means for moving the blades along a rail or trolley in response to operator direction or some other control means. U.S. Pat. Nos. 4,505,174, 4,641,556 and 4,662,258 exemplify this type of prior art apparatus and cutting method.
All of the prior art methods and apparatus possess major shortcomings, most notable being the inability to cut at high speed with repeatable accuracy and the total inability to cut non-linear windows and designs in the mat board. Blade cutting techniques of necessity require that the blade be unsupported over the length extended into the mat board, which in prior art devices causes lateral blade flex, and resistance of the board to the linear advancement of the blade causes blade wander, wobble or flutter in response to the resistance of the board if the blade is moved too fast or laterally stressed to any great extent. Attempts have been made to solve the former problem, see U.S. Pat. No. 4,662,258 referenced above, but the latter problem remains unsolved. Moreover, attempting to cut arcs, particularly arcs of small radius, such as under one foot radius, aggravates the flexing of the blades by placing them under stress from several directions, resulting in uneven bevel angles and resulting borders of different widths, and a defective product.